Abstract
Despite being a tropical country, vitamin D deficiency is common in Singapore. All young Singaporean males between the age of 18 and 21 years have to undergo mandatory military service. Stress fractures occur in military recruits, and risk factors include a sudden increase in physical activity and vitamin D deficiency. We report the bone histomorphometry findings from a case of bilateral tibial stress fractures in an 18-year-old military recruit who had vitamin D deficiency. The histomorphometry showed a mixed osteomalacia and osteoporosis pattern. This case is unique as it shows that stress fractures from a marching exercise can occur in apparently healthy well young man with vitamin D deficiency despite living in a tropical country.